Study Summary: The evolutionary mismatch hypothesis: Implications for psychological science

Study Summary: The evolutionary mismatch hypothesis: Implications for psychological science

Keywords: mismatch, adaptive lag, supernormal stimuli, evolutionary psychology

Authors: Norman Li, Mark Vugt, Stephen Colarelli

Date: 2018

Abstract

Human psychological mechanisms are adaptations that evolved to process environmental inputs, turning them into behavioral outputs that, on average, increase survival or reproductive prospects. Modern contexts, however, differ vastly from the environments that existed as human psychological mechanisms evolved. Many inputs now differ in quantity and intensity or no longer have the same fitness associations, thereby leading many mechanisms to produce maladaptive output. We present the precepts of this evolutionary mismatch process, highlight areas of mismatch, and consider implications for psychological science and policy.

Types Of Mismatch

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  • Source
    • Natural
    • Human Change
  • Type
    • Forced. When an environment is imposed on an organism.
    • Hijacked. When novel stimuli are favored by a mechanism over stimuli that the mechanism evolved to process.
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Mismatch occurs because of significant changes in either (a) input cues, which have changed in intensity or quantity, are altogether missing, or have been replaced by novel cues mimicking the original cues, or (b) the consequences of the mechanism’s output. Mismatch can positively or negatively affect both a mechanism’s impact on reproductive fitness and the degree to which the mechanism’s outputs align with individuals’ well-being or values. Importantly, these two aspects are separate considerations. Also, while we focus on evolutionary mismatches, novel environments may also create developmental mismatches (e.g., prenatal undernutrition; Frankenhuis & Del Giudice, 2012) or cultural mismatches (e.g., living in a totalitarian state).

What's New In The Modern Environment

  • Higher population densities
  • Greater dispersal of families
  • Proliferation of attractive individuals encountered electronically
  • Exposed to less nature
  • More sedentary
  • Ingest processed foods and substances.
Accordingly, psychological and physiological mechanisms that process these types of inputs are particularly likely to be affected by mismatch. Such mechanisms include ones that assess mate value and mating opportunities, reproductive timing, relationship commitment, life satisfaction, competition, resource and social support availability, and nutrition (e.g., Kanazawa & Li, 2015; Yong, Li, Valentine, & Smith, 2017).

Examples Of Mismatches

Sweets: Sweet tastes in ancestral environments were associated with foods such as fruit, yams, and honey that have naturally useful levels of carbohydrates and nutrients. Accordingly, a decision rule of “prefer and eat the sweetest-tasting things” led to beneficial consumption of such foods (Fig. 1a). Today, however, the sweetest tastes belong to readily available foods manufactured with copious amounts of processed sugars and stripped of nutrients (Fig. 1b). These mismatched food sources then lead to illnesses such as diabetes because physiological mechanisms involving insulin and glucagon did not evolve to repeatedly metabolize unnaturally large amounts of sugar (Gluckman & Hanson, 2006).

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Conclusion

As societies globalize and human-induced environmental change occurs progressively faster, evolutionary mismatch is only becoming increasingly prevalent. Given that mismatch often brings negative consequences for physical and psychological health and values, understanding the mismatch process is important not only for basic psychological science research but also for achieving key insights into more effective avenues to address the numerous problems of the modern world.

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